The present invention relates to a tool for threading wire through walls.
Telephone and cable television installers must frequently thread cables through walls where holes have been drilled to accommodate electrical cables. Often the walls are double walls, that is, the cable must be threaded through a first or interior wall partition and a second or exterior wall partition. Frequently, insulation is stuffed into the space between the wall partitions. This presents a problem, especially with cables that have little tensile strength, as the cables bend and cannot be forced through the space between the wall partitions. Sometimes the holes must be drilled separately because of the insulation residing between the walls. The problem is also encountered in floors where there is subflooring with insulation beneath it and in ceilings where insulation has been piled in the attic on top of the ceiling.
Many complicated devices have been developed for drilling holes and installing wires or cables therethrough. Two examples of such devices are disclosed in Pope, U.S. Pat. No. 3,697,188, and Flener, U.S. Pat. No. 5,529,433. Both of these devices are relatively complicated. Further, as holes are often already bored, such as in the case of a reinstallation of a faulty wire or where a second telephone line is to be added, drilling is often unnecessary. Perkins, U.S. Pat. No. 5,310,294, discloses another device in which a cutting element bores a hole through a wall. Then, before removing the cutting element, a wire attachment apparatus is coupled to the cutting element. The wire cutting element, with the attached wire attachment apparatus and wire, is then pulled through the hole. Again, if the holes are already bored, this device is overly complicated and the cutting apparatus is unnecessary.
Other devices have been developed to catch a loose or hooked end of a cable within a narrow structure such as a wall. Caracofe et al., U.S. Pat. No. 5,458,317 and Comroe, U.S. Pat. No. 4,230,305, disclose devices that can catch, grab, or otherwise receive a pre-threaded cable. These devices are necessary when the cable is being threaded long distances through walls. These devices are particularly suited to situations where the first hole is above the second hole. However, because these devices require relatively large openings in the wall in order to insert their catching ends, they should only be used when absolutely necessary.
The device described in Stegall, U.S. Pat. No. 4,386,800, is used for pulling wire through pre-drilled holes. This device, however, includes multiple parts including cable grasping fingers. These parts, particularly the cable grasping fingers, could easily break, could easily be bent, or could easily become lost. Also, because the cable must be inserted into the sleeve, the size (outer diameter) of the cable to be pulled through the wall is strictly limited by the inner diameter of the sleeve.
What is needed then is a simple device that is capable of threading wire or cable through pre-drilled holes in a wall, ceiling, or flooring. The device should be sturdy and adaptable to multiple types and sizes of wire and cable.